Advancements in photography have brought about a need for novel methods for processing digital images. The digital camera, though in its infancy, may nearly replace conventional imaging techniques as advancements in digital imagery proliferate. The development of digital photography includes creating high quality single shot images using a CCD (Charge-Coupled Device) chip which houses thousands of “sensors” sensitive for red, green and blue light. Via interpolation, a built-in or external computer recalculates the original color of each pixel.
A large problem to overcome for camera designers is the resolution of the CCD. More “sensors” mean higher resolutions, but it's technical difficult to create CCD chips with larger surfaces (larger “negative” format) with more “sensors”. The last few years have brought a breakthrough and resolution is becoming acceptable for professional use. Modern CCD's on 6×6 cm “neg.” format are housing up to 6,000,000 pixels, enough for A4 output.
During use, light passes through the lens of a digital camera the same way it does a regular camera. Instead of being focused on photographic film, the image is focused on a chip called a charge-coupled device (CCD). The top of the CCD is covered with transistors that create electrical currents in proportion to the intensity of the light striking them. The transistors make up the pixels of the image. A pixel is the minimum, distinct visual piece of information that a component can display or capture. The pixel can be made up of only one transistor for black and white photography or several transistors for color. The more pixels in an image, the better the resolution. The transistors create a continuous, analog electrical signal that goes to an analog-to-digital converter—(ADC). The ADC is a chip that translates the varying signal to a digital format, which consists of a continuous stream of 1's and 0's.
The ADC sends the digital information to a digital signal processor (DSP)—that has been programmed specifically to create photographic images. The DSP adjusts the contrast and detail in the image, compresses the data that makes up the image so that it takes up less storage space, and sends the data to the camera's storage medium.